The jump to version 7.0.0 of @babel/core represents a significant milestone for Babel, marking a shift with substantial changes that developers should be aware of. While specifics of the previous stable version remain undefined in the query data, it's safe to assume version 7.0.0 includes considerable API updates and potential performance enhancements. The dependency list alone indicates a deep integration with other @babel packages, such as @babel/types, @babel/parser, @babel/helpers, @babel/template, @babel/traverse, @babel/generator, and @babel/code-frame, highlighting a modular and cohesive ecosystem. These dependencies underscore the library's strong focus on handling various aspects of JavaScript code transformation, from parsing and abstract syntax tree (AST) manipulation to code generation and error reporting.
The inclusion of debug, json5, lodash, semver, resolve, and source-map speaks to the tool's maturity and commitment to providing comprehensive features for debugging, configuration, utility functions, version management, module resolution, and source map generation. Such features are especially valuable in complex projects with debugging needs. The devDependencies section, featuring @babel/register and @babel/helper-transform-fixture-test-runner, points to a strong emphasis on testing and integration within Babel's own development workflow, which indirectly benefits users through potentially more reliable and stable releases. Given the "MIT" license and the repository link to GitHub, developers have clear access to the code and are free to use, modify, and distribute babel in their projects.
All the vulnerabilities related to the version 7.0.0 of the package
Prototype Pollution in JSON5 via Parse Method
The parse method of the JSON5 library before and including version 2.2.1 does not restrict parsing of keys named __proto__, allowing specially crafted strings to pollute the prototype of the resulting object.
This vulnerability pollutes the prototype of the object returned by JSON5.parse and not the global Object prototype, which is the commonly understood definition of Prototype Pollution. However, polluting the prototype of a single object can have significant security impact for an application if the object is later used in trusted operations.
This vulnerability could allow an attacker to set arbitrary and unexpected keys on the object returned from JSON5.parse. The actual impact will depend on how applications utilize the returned object and how they filter unwanted keys, but could include denial of service, cross-site scripting, elevation of privilege, and in extreme cases, remote code execution.
This vulnerability is patched in json5 v2.2.2 and later. A patch has also been backported for json5 v1 in versions v1.0.2 and later.
Suppose a developer wants to allow users and admins to perform some risky operation, but they want to restrict what non-admins can do. To accomplish this, they accept a JSON blob from the user, parse it using JSON5.parse, confirm that the provided data does not set some sensitive keys, and then performs the risky operation using the validated data:
const JSON5 = require('json5');
const doSomethingDangerous = (props) => {
if (props.isAdmin) {
console.log('Doing dangerous thing as admin.');
} else {
console.log('Doing dangerous thing as user.');
}
};
const secCheckKeysSet = (obj, searchKeys) => {
let searchKeyFound = false;
Object.keys(obj).forEach((key) => {
if (searchKeys.indexOf(key) > -1) {
searchKeyFound = true;
}
});
return searchKeyFound;
};
const props = JSON5.parse('{"foo": "bar"}');
if (!secCheckKeysSet(props, ['isAdmin', 'isMod'])) {
doSomethingDangerous(props); // "Doing dangerous thing as user."
} else {
throw new Error('Forbidden...');
}
If the user attempts to set the isAdmin key, their request will be rejected:
const props = JSON5.parse('{"foo": "bar", "isAdmin": true}');
if (!secCheckKeysSet(props, ['isAdmin', 'isMod'])) {
doSomethingDangerous(props);
} else {
throw new Error('Forbidden...'); // Error: Forbidden...
}
However, users can instead set the __proto__ key to {"isAdmin": true}. JSON5 will parse this key and will set the isAdmin key on the prototype of the returned object, allowing the user to bypass the security check and run their request as an admin:
const props = JSON5.parse('{"foo": "bar", "__proto__": {"isAdmin": true}}');
if (!secCheckKeysSet(props, ['isAdmin', 'isMod'])) {
doSomethingDangerous(props); // "Doing dangerous thing as admin."
} else {
throw new Error('Forbidden...');
}